BEIRUT: Fighters from an al Qaeda-linked rebel group killed 12 members of the minority Alawite sect in central Syria after seizing their village, an opposition monitoring group said on Wednesday.

Alawites are an offshoot sect of Shi'ite Islam and have been increasingly targeted by radical fighters among the Sunni Muslim-dominated opposition in the 2-1/2 year revolt against President Bashar al-Assad, himself an Alawite.

Under four decades of Assad family rule, Alawites have made up most of the political and military elite in Syria. The rise of hardline Islamists in the rebellion and the possibility of major attacks on minorities like Alawites have contributed to a Western hesitancy to intervene directly in the conflict.

The latest killings occurred after rebels of the Nusra Front, which is affiliated with al Qaeda, stormed the village of Maksar al-Hesan east of the city of Homs on Tuesday, the Britain-based Syrian Observatory for Human Rights said.

The Observatory, which has a network of sources across Syria, cited residents and medics in its report.

Nusra Front fighters then shot dead at least 12 Alawite civilians in the village, the Observatory's director Rami Abdelrahman said, including some women and elderly.

He said the reason behind the killings was unclear, but they may have been executions.

Waleed al-Fares, an activist in Homs, denied rebels had killed civilians in the area and said that Alawites who died on Tuesday were killed while fighting on the government's side.

Al Qaeda-associated groups in the opposition have pledged to avenge an apparent chemical weapons attack outside Damascus that killed between 500 and 1,400 people on August 21, according to activist reports. The opposition and Western powers say Assad's forces were behind the attack. His government denies it.

The Islamist insurgents' "Eye for an Eye" campaign has targeted Alawite areas in particular.

Within hours after Nusra fighters swept into Maksar al-Hesan, government forces retook the village in clashes that killed at least two government fighters and a number of rebels, the Observatory said.

U.S. President Barack Obama had been pushing for a military strike on Syria to punish Assad for the chemical weapons attack, but has been held up by domestic and international political wrangling.

On Tuesday Obama pledged to explore a Russian proposal for Syria to place its chemical weapons under international control but pledged to keep military forces ready to strike if it failed.

Ground fighting and air strikes have continued in nearly every province of Syria, often killing more than 1,000 people a week.

Some 3,000 people - around a third of them civilians - have been killed in Syria since August 22, the day after the alleged chemical attack, according to the Observatory.

In a separate incident on Tuesday, unknown gunmen killed a family of four from al-Matras, a village of minority Turkmen in the coastal Tartous province, the Observatory said.